[deliverable/linux.git] / security / integrity / ima / ima_api.c

/*
 * Copyright (C) 2008 IBM Corporation
 *
 * Author: Mimi Zohar <zohar@us.ibm.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, version 2 of the
 * License.
 *
 * File: ima_api.c
 *	Implements must_appraise_or_measure, collect_measurement,
 *	appraise_measurement, store_measurement and store_template.
 */
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/xattr.h>
#include <linux/evm.h>
#include <crypto/hash_info.h>
#include "ima.h"

/*
 * ima_alloc_init_template - create and initialize a new template entry
 */
int ima_alloc_init_template(struct integrity_iint_cache *iint,
			    struct file *file, const unsigned char *filename,
			    struct evm_ima_xattr_data *xattr_value,
			    int xattr_len, struct ima_template_entry **entry)
{
	struct ima_template_desc *template_desc = ima_template_desc_current();
	int i, result = 0;

	*entry = kzalloc(sizeof(**entry) + template_desc->num_fields *
			 sizeof(struct ima_field_data), GFP_NOFS);
	if (!*entry)
		return -ENOMEM;

	for (i = 0; i < template_desc->num_fields; i++) {
		struct ima_template_field *field = template_desc->fields[i];
		u32 len;

		result = field->field_init(iint, file, filename,
					   xattr_value, xattr_len,
					   &((*entry)->template_data[i]));
		if (result != 0)
			goto out;

		len = (*entry)->template_data[i].len;
		(*entry)->template_data_len += sizeof(len);
		(*entry)->template_data_len += len;
	}
	(*entry)->template_desc = template_desc;
	return 0;
out:
	kfree(*entry);
	*entry = NULL;
	return result;
}

/*
 * ima_store_template - store ima template measurements
 *
 * Calculate the hash of a template entry, add the template entry
 * to an ordered list of measurement entries maintained inside the kernel,
 * and also update the aggregate integrity value (maintained inside the
 * configured TPM PCR) over the hashes of the current list of measurement
 * entries.
 *
 * Applications retrieve the current kernel-held measurement list through
 * the securityfs entries in /sys/kernel/security/ima. The signed aggregate
 * TPM PCR (called quote) can be retrieved using a TPM user space library
 * and is used to validate the measurement list.
 *
 * Returns 0 on success, error code otherwise
 */
int ima_store_template(struct ima_template_entry *entry,
		       int violation, struct inode *inode,
		       const unsigned char *filename)
{
	const char *op = "add_template_measure";
	const char *audit_cause = "hashing_error";
	char *template_name = entry->template_desc->name;
	int result;
	struct {
		struct ima_digest_data hdr;
		char digest[TPM_DIGEST_SIZE];
	} hash;

	if (!violation) {
		int num_fields = entry->template_desc->num_fields;

		/* this function uses default algo */
		hash.hdr.algo = HASH_ALGO_SHA1;
		result = ima_calc_field_array_hash(&entry->template_data[0],
						   num_fields, &hash.hdr);
		if (result < 0) {
			integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode,
					    template_name, op,
					    audit_cause, result, 0);
			return result;
		}
		memcpy(entry->digest, hash.hdr.digest, hash.hdr.length);
	}
	result = ima_add_template_entry(entry, violation, op, inode, filename);
	return result;
}

/*
 * ima_add_violation - add violation to measurement list.
 *
 * Violations are flagged in the measurement list with zero hash values.
 * By extending the PCR with 0xFF's instead of with zeroes, the PCR
 * value is invalidated.
 */
void ima_add_violation(struct file *file, const unsigned char *filename,
		       const char *op, const char *cause)
{
	struct ima_template_entry *entry;
	struct inode *inode = file->f_dentry->d_inode;
	int violation = 1;
	int result;

	/* can overflow, only indicator */
	atomic_long_inc(&ima_htable.violations);

	result = ima_alloc_init_template(NULL, file, filename,
					 NULL, 0, &entry);
	if (result < 0) {
		result = -ENOMEM;
		goto err_out;
	}
	result = ima_store_template(entry, violation, inode, filename);
	if (result < 0)
		kfree(entry);
err_out:
	integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
			    op, cause, result, 0);
}

/**
 * ima_get_action - appraise & measure decision based on policy.
 * @inode: pointer to inode to measure
 * @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXECUTE)
 * @function: calling function (FILE_CHECK, BPRM_CHECK, MMAP_CHECK, MODULE_CHECK)
 *
 * The policy is defined in terms of keypairs:
 * 		subj=, obj=, type=, func=, mask=, fsmagic=
 *	subj,obj, and type: are LSM specific.
 * 	func: FILE_CHECK | BPRM_CHECK | MMAP_CHECK | MODULE_CHECK
 * 	mask: contains the permission mask
 *	fsmagic: hex value
 *
 * Returns IMA_MEASURE, IMA_APPRAISE mask.
 *
 */
int ima_get_action(struct inode *inode, int mask, int function)
{
	int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE;

	if (!ima_appraise)
		flags &= ~IMA_APPRAISE;

	return ima_match_policy(inode, function, mask, flags);
}

int ima_must_measure(struct inode *inode, int mask, int function)
{
	return ima_match_policy(inode, function, mask, IMA_MEASURE);
}

/*
 * ima_collect_measurement - collect file measurement
 *
 * Calculate the file hash, if it doesn't already exist,
 * storing the measurement and i_version in the iint.
 *
 * Must be called with iint->mutex held.
 *
 * Return 0 on success, error code otherwise
 */
int ima_collect_measurement(struct integrity_iint_cache *iint,
			    struct file *file,
			    struct evm_ima_xattr_data **xattr_value,
			    int *xattr_len)
{
	struct inode *inode = file_inode(file);
	const char *filename = file->f_dentry->d_name.name;
	int result = 0;
	struct {
		struct ima_digest_data hdr;
		char digest[IMA_MAX_DIGEST_SIZE];
	} hash;

	if (xattr_value)
		*xattr_len = ima_read_xattr(file->f_dentry, xattr_value);

	if (!(iint->flags & IMA_COLLECTED)) {
		u64 i_version = file_inode(file)->i_version;

		/* use default hash algorithm */
		hash.hdr.algo = ima_hash_algo;

		if (xattr_value)
			ima_get_hash_algo(*xattr_value, *xattr_len, &hash.hdr);

		result = ima_calc_file_hash(file, &hash.hdr);
		if (!result) {
			int length = sizeof(hash.hdr) + hash.hdr.length;
			void *tmpbuf = krealloc(iint->ima_hash, length,
						GFP_NOFS);
			if (tmpbuf) {
				iint->ima_hash = tmpbuf;
				memcpy(iint->ima_hash, &hash, length);
				iint->version = i_version;
				iint->flags |= IMA_COLLECTED;
			} else
				result = -ENOMEM;
		}
	}
	if (result)
		integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode,
				    filename, "collect_data", "failed",
				    result, 0);
	return result;
}

/*
 * ima_store_measurement - store file measurement
 *
 * Create an "ima" template and then store the template by calling
 * ima_store_template.
 *
 * We only get here if the inode has not already been measured,
 * but the measurement could already exist:
 * 	- multiple copies of the same file on either the same or
 *	  different filesystems.
 *	- the inode was previously flushed as well as the iint info,
 *	  containing the hashing info.
 *
 * Must be called with iint->mutex held.
 */
void ima_store_measurement(struct integrity_iint_cache *iint,
			   struct file *file, const unsigned char *filename,
			   struct evm_ima_xattr_data *xattr_value,
			   int xattr_len)
{
	const char *op = "add_template_measure";
	const char *audit_cause = "ENOMEM";
	int result = -ENOMEM;
	struct inode *inode = file_inode(file);
	struct ima_template_entry *entry;
	int violation = 0;

	if (iint->flags & IMA_MEASURED)
		return;

	result = ima_alloc_init_template(iint, file, filename,
					 xattr_value, xattr_len, &entry);
	if (result < 0) {
		integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
				    op, audit_cause, result, 0);
		return;
	}

	result = ima_store_template(entry, violation, inode, filename);
	if (!result || result == -EEXIST)
		iint->flags |= IMA_MEASURED;
	if (result < 0)
		kfree(entry);
}

void ima_audit_measurement(struct integrity_iint_cache *iint,
			   const unsigned char *filename)
{
	struct audit_buffer *ab;
	char hash[(iint->ima_hash->length * 2) + 1];
	const char *algo_name = hash_algo_name[iint->ima_hash->algo];
	char algo_hash[sizeof(hash) + strlen(algo_name) + 2];
	int i;

	if (iint->flags & IMA_AUDITED)
		return;

	for (i = 0; i < iint->ima_hash->length; i++)
		hex_byte_pack(hash + (i * 2), iint->ima_hash->digest[i]);
	hash[i * 2] = '\0';

	ab = audit_log_start(current->audit_context, GFP_KERNEL,
			     AUDIT_INTEGRITY_RULE);
	if (!ab)
		return;

	audit_log_format(ab, "file=");
	audit_log_untrustedstring(ab, filename);
	audit_log_format(ab, " hash=");
	snprintf(algo_hash, sizeof(algo_hash), "%s:%s", algo_name, hash);
	audit_log_untrustedstring(ab, algo_hash);

	audit_log_task_info(ab, current);
	audit_log_end(ab);

	iint->flags |= IMA_AUDITED;
}

const char *ima_d_path(struct path *path, char **pathbuf)
{
	char *pathname = NULL;

	/* We will allow 11 spaces for ' (deleted)' to be appended */
	*pathbuf = kmalloc(PATH_MAX + 11, GFP_KERNEL);
	if (*pathbuf) {
		pathname = d_path(path, *pathbuf, PATH_MAX + 11);
		if (IS_ERR(pathname)) {
			kfree(*pathbuf);
			*pathbuf = NULL;
			pathname = NULL;
		}
	}
	return pathname;
}
Commit	Line	Data
3323eec9 MZ	1	/*
	2	* Copyright (C) 2008 IBM Corporation
	3	*
	4	* Author: Mimi Zohar <zohar@us.ibm.com>
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License as
	8	* published by the Free Software Foundation, version 2 of the
	9	* License.
	10	*
	11	* File: ima_api.c
2fe5d6de MZ	12	* Implements must_appraise_or_measure, collect_measurement,
2fe5d6de MZ	13	* appraise_measurement, store_measurement and store_template.
3323eec9 MZ	14	*/
3323eec9 MZ	15	#include <linux/module.h>
5a0e3ad6	16	#include <linux/slab.h>
2fe5d6de MZ	17	#include <linux/file.h>
	18	#include <linux/fs.h>
	19	#include <linux/xattr.h>
	20	#include <linux/evm.h>
ea593993	21	#include <crypto/hash_info.h>
3323eec9	22	#include "ima.h"
2fe5d6de	23
7bc5f447 RS	24	/*
	25	* ima_alloc_init_template - create and initialize a new template entry
	26	*/
	27	int ima_alloc_init_template(struct integrity_iint_cache *iint,
	28	struct file file, const unsigned char filename,
bcbc9b0c MZ	29	struct evm_ima_xattr_data *xattr_value,
bcbc9b0c MZ	30	int xattr_len, struct ima_template_entry **entry)
7bc5f447	31	{
a71dc65d RS	32	struct ima_template_desc *template_desc = ima_template_desc_current();
a71dc65d RS	33	int i, result = 0;
7bc5f447	34
a71dc65d RS	35	entry = kzalloc(sizeof(entry) + template_desc->num_fields
	36	sizeof(struct ima_field_data), GFP_NOFS);
	37	if (!*entry)
7bc5f447 RS	38	return -ENOMEM;
7bc5f447 RS	39
a71dc65d RS	40	for (i = 0; i < template_desc->num_fields; i++) {
	41	struct ima_template_field *field = template_desc->fields[i];
	42	u32 len;
7bc5f447	43
a71dc65d	44	result = field->field_init(iint, file, filename,
bcbc9b0c	45	xattr_value, xattr_len,
a71dc65d RS	46	&((*entry)->template_data[i]));
	47	if (result != 0)
	48	goto out;
7bc5f447	49
a71dc65d RS	50	len = (*entry)->template_data[i].len;
	51	(*entry)->template_data_len += sizeof(len);
	52	(*entry)->template_data_len += len;
	53	}
	54	(*entry)->template_desc = template_desc;
7bc5f447	55	return 0;
a71dc65d RS	56	out:
	57	kfree(*entry);
	58	*entry = NULL;
7bc5f447 RS	59	return result;
	60	}
	61
3323eec9 MZ	62	/*
	63	* ima_store_template - store ima template measurements
	64	*
	65	* Calculate the hash of a template entry, add the template entry
	66	* to an ordered list of measurement entries maintained inside the kernel,
	67	* and also update the aggregate integrity value (maintained inside the
	68	* configured TPM PCR) over the hashes of the current list of measurement
	69	* entries.
	70	*
	71	* Applications retrieve the current kernel-held measurement list through
	72	* the securityfs entries in /sys/kernel/security/ima. The signed aggregate
	73	* TPM PCR (called quote) can be retrieved using a TPM user space library
	74	* and is used to validate the measurement list.
	75	*
	76	* Returns 0 on success, error code otherwise
	77	*/
	78	int ima_store_template(struct ima_template_entry *entry,
9803d413 RS	79	int violation, struct inode *inode,
9803d413 RS	80	const unsigned char *filename)
3323eec9 MZ	81	{
	82	const char *op = "add_template_measure";
	83	const char *audit_cause = "hashing_error";
a71dc65d	84	char *template_name = entry->template_desc->name;
3323eec9	85	int result;
a35c3fb6 DK	86	struct {
a35c3fb6 DK	87	struct ima_digest_data hdr;
140d8022	88	char digest[TPM_DIGEST_SIZE];
a35c3fb6	89	} hash;
3323eec9	90
3323eec9	91	if (!violation) {
a71dc65d RS	92	int num_fields = entry->template_desc->num_fields;
a71dc65d RS	93
ea593993 DK	94	/* this function uses default algo */
ea593993 DK	95	hash.hdr.algo = HASH_ALGO_SHA1;
a71dc65d RS	96	result = ima_calc_field_array_hash(&entry->template_data[0],
a71dc65d RS	97	num_fields, &hash.hdr);
3323eec9 MZ	98	if (result < 0) {
3323eec9 MZ	99	integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode,
a71dc65d	100	template_name, op,
3323eec9 MZ	101	audit_cause, result, 0);
	102	return result;
	103	}
a35c3fb6	104	memcpy(entry->digest, hash.hdr.digest, hash.hdr.length);
3323eec9	105	}
9803d413	106	result = ima_add_template_entry(entry, violation, op, inode, filename);
3323eec9 MZ	107	return result;
	108	}
	109
	110	/*
	111	* ima_add_violation - add violation to measurement list.
	112	*
	113	* Violations are flagged in the measurement list with zero hash values.
	114	* By extending the PCR with 0xFF's instead of with zeroes, the PCR
	115	* value is invalidated.
	116	*/
7d802a22	117	void ima_add_violation(struct file file, const unsigned char filename,
3323eec9 MZ	118	const char op, const char cause)
	119	{
	120	struct ima_template_entry *entry;
7d802a22	121	struct inode *inode = file->f_dentry->d_inode;
3323eec9 MZ	122	int violation = 1;
	123	int result;
	124
	125	/* can overflow, only indicator */
	126	atomic_long_inc(&ima_htable.violations);
	127
bcbc9b0c MZ	128	result = ima_alloc_init_template(NULL, file, filename,
bcbc9b0c MZ	129	NULL, 0, &entry);
7bc5f447	130	if (result < 0) {
3323eec9 MZ	131	result = -ENOMEM;
	132	goto err_out;
	133	}
9803d413	134	result = ima_store_template(entry, violation, inode, filename);
3323eec9 MZ	135	if (result < 0)
	136	kfree(entry);
	137	err_out:
	138	integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
	139	op, cause, result, 0);
	140	}
	141
	142	/**
d9d300cd	143	* ima_get_action - appraise & measure decision based on policy.
3323eec9 MZ	144	* @inode: pointer to inode to measure
3323eec9 MZ	145	* @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXECUTE)
16cac49f	146	* @function: calling function (FILE_CHECK, BPRM_CHECK, MMAP_CHECK, MODULE_CHECK)
3323eec9 MZ	147	*
	148	* The policy is defined in terms of keypairs:
	149	* subj=, obj=, type=, func=, mask=, fsmagic=
	150	* subj,obj, and type: are LSM specific.
16cac49f	151	* func: FILE_CHECK \| BPRM_CHECK \| MMAP_CHECK \| MODULE_CHECK
3323eec9 MZ	152	* mask: contains the permission mask
	153	* fsmagic: hex value
	154	*
2fe5d6de MZ	155	* Returns IMA_MEASURE, IMA_APPRAISE mask.
	156	*
	157	*/
d9d300cd	158	int ima_get_action(struct inode *inode, int mask, int function)
3323eec9	159	{
e7c568e0	160	int flags = IMA_MEASURE \| IMA_AUDIT \| IMA_APPRAISE;
2fe5d6de MZ	161
	162	if (!ima_appraise)
	163	flags &= ~IMA_APPRAISE;
	164
	165	return ima_match_policy(inode, function, mask, flags);
	166	}
3323eec9	167
2fe5d6de MZ	168	int ima_must_measure(struct inode *inode, int mask, int function)
	169	{
	170	return ima_match_policy(inode, function, mask, IMA_MEASURE);
3323eec9 MZ	171	}
	172
	173	/*
	174	* ima_collect_measurement - collect file measurement
	175	*
	176	* Calculate the file hash, if it doesn't already exist,
	177	* storing the measurement and i_version in the iint.
	178	*
	179	* Must be called with iint->mutex held.
	180	*
	181	* Return 0 on success, error code otherwise
	182	*/
f381c272	183	int ima_collect_measurement(struct integrity_iint_cache *iint,
d3634d0f DK	184	struct file *file,
	185	struct evm_ima_xattr_data **xattr_value,
	186	int *xattr_len)
3323eec9	187	{
496ad9aa	188	struct inode *inode = file_inode(file);
2fe5d6de MZ	189	const char *filename = file->f_dentry->d_name.name;
2fe5d6de MZ	190	int result = 0;
a35c3fb6 DK	191	struct {
	192	struct ima_digest_data hdr;
	193	char digest[IMA_MAX_DIGEST_SIZE];
	194	} hash;
3323eec9	195
d3634d0f DK	196	if (xattr_value)
	197	*xattr_len = ima_read_xattr(file->f_dentry, xattr_value);
	198
2fe5d6de	199	if (!(iint->flags & IMA_COLLECTED)) {
496ad9aa	200	u64 i_version = file_inode(file)->i_version;
3323eec9	201
c7c8bb23	202	/* use default hash algorithm */
a35c3fb6	203	hash.hdr.algo = ima_hash_algo;
d3634d0f DK	204
d3634d0f DK	205	if (xattr_value)
a35c3fb6	206	ima_get_hash_algo(xattr_value, xattr_len, &hash.hdr);
d3634d0f	207
a35c3fb6	208	result = ima_calc_file_hash(file, &hash.hdr);
2fe5d6de	209	if (!result) {
a35c3fb6 DK	210	int length = sizeof(hash.hdr) + hash.hdr.length;
	211	void *tmpbuf = krealloc(iint->ima_hash, length,
	212	GFP_NOFS);
	213	if (tmpbuf) {
	214	iint->ima_hash = tmpbuf;
	215	memcpy(iint->ima_hash, &hash, length);
	216	iint->version = i_version;
	217	iint->flags \|= IMA_COLLECTED;
	218	} else
	219	result = -ENOMEM;
2fe5d6de	220	}
3323eec9	221	}
2fe5d6de MZ	222	if (result)
	223	integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode,
	224	filename, "collect_data", "failed",
	225	result, 0);
3323eec9 MZ	226	return result;
	227	}
	228
	229	/*
	230	* ima_store_measurement - store file measurement
	231	*
	232	* Create an "ima" template and then store the template by calling
	233	* ima_store_template.
	234	*
	235	* We only get here if the inode has not already been measured,
	236	* but the measurement could already exist:
	237	* - multiple copies of the same file on either the same or
	238	* different filesystems.
	239	* - the inode was previously flushed as well as the iint info,
	240	* containing the hashing info.
	241	*
	242	* Must be called with iint->mutex held.
	243	*/
f381c272	244	void ima_store_measurement(struct integrity_iint_cache *iint,
bcbc9b0c MZ	245	struct file file, const unsigned char filename,
	246	struct evm_ima_xattr_data *xattr_value,
	247	int xattr_len)
3323eec9 MZ	248	{
	249	const char *op = "add_template_measure";
	250	const char *audit_cause = "ENOMEM";
	251	int result = -ENOMEM;
496ad9aa	252	struct inode *inode = file_inode(file);
3323eec9 MZ	253	struct ima_template_entry *entry;
	254	int violation = 0;
	255
2fe5d6de MZ	256	if (iint->flags & IMA_MEASURED)
	257	return;
	258
bcbc9b0c MZ	259	result = ima_alloc_init_template(iint, file, filename,
bcbc9b0c MZ	260	xattr_value, xattr_len, &entry);
7bc5f447	261	if (result < 0) {
3323eec9 MZ	262	integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
	263	op, audit_cause, result, 0);
	264	return;
	265	}
3323eec9	266
9803d413	267	result = ima_store_template(entry, violation, inode, filename);
45fae749	268	if (!result \|\| result == -EEXIST)
3323eec9	269	iint->flags \|= IMA_MEASURED;
45fae749	270	if (result < 0)
3323eec9 MZ	271	kfree(entry);
3323eec9 MZ	272	}
e7c568e0 PM	273
	274	void ima_audit_measurement(struct integrity_iint_cache *iint,
	275	const unsigned char *filename)
	276	{
	277	struct audit_buffer *ab;
a35c3fb6	278	char hash[(iint->ima_hash->length * 2) + 1];
5278aa52 MZ	279	const char *algo_name = hash_algo_name[iint->ima_hash->algo];
5278aa52 MZ	280	char algo_hash[sizeof(hash) + strlen(algo_name) + 2];
e7c568e0 PM	281	int i;
	282
	283	if (iint->flags & IMA_AUDITED)
	284	return;
	285
a35c3fb6 DK	286	for (i = 0; i < iint->ima_hash->length; i++)
a35c3fb6 DK	287	hex_byte_pack(hash + (i * 2), iint->ima_hash->digest[i]);
e7c568e0 PM	288	hash[i * 2] = '\0';
	289
	290	ab = audit_log_start(current->audit_context, GFP_KERNEL,
	291	AUDIT_INTEGRITY_RULE);
	292	if (!ab)
	293	return;
	294
	295	audit_log_format(ab, "file=");
	296	audit_log_untrustedstring(ab, filename);
	297	audit_log_format(ab, " hash=");
5278aa52 MZ	298	snprintf(algo_hash, sizeof(algo_hash), "%s:%s", algo_name, hash);
5278aa52 MZ	299	audit_log_untrustedstring(ab, algo_hash);
e7c568e0 PM	300
	301	audit_log_task_info(ab, current);
	302	audit_log_end(ab);
	303
	304	iint->flags \|= IMA_AUDITED;
	305	}
ea1046d4 DK	306
	307	const char ima_d_path(struct path path, char **pathbuf)
	308	{
	309	char *pathname = NULL;
	310
	311	/* We will allow 11 spaces for ' (deleted)' to be appended */
	312	*pathbuf = kmalloc(PATH_MAX + 11, GFP_KERNEL);
	313	if (*pathbuf) {
	314	pathname = d_path(path, *pathbuf, PATH_MAX + 11);
	315	if (IS_ERR(pathname)) {
	316	kfree(*pathbuf);
	317	*pathbuf = NULL;
	318	pathname = NULL;
	319	}
	320	}
	321	return pathname;
	322	}